A semiconductor package (hereinafter also simply referred to as “package”) is used for storing a semiconductor, protecting the semiconductor against the external environment and mounting the same on a printed board or the like. Such semiconductor packages are classified into a surface-mount type and an insertion-mount type depending on methods of mounting the same on substrates.
A surface-mount type package includes a BGA (Ball Grid Array), for example, which is mounted by directly soldering solder balls arranged on a base surface of the package at a constant interval in a latticelike manner to soldering patterns (mount pads) provided on the surface of a substrate. An insertion-mount type package includes a PGA (Pin Grid Array), for example, which is mounted by inserting pin electrodes vertically taken out from the package body into socket electrodes of a substrate. Following high integration and speed-up of hodiernal semiconductors as well as miniaturization/weight reduction of electronic devices, high-density mounting and miniaturization of semiconductors are required.
The surface-mount type package, allowing refinement of the soldering patterns on the surface of the substrate and the solder balls and mountable on either side of the substrate, has a structure easy to densify. If once mounted, however, the surface-mount type package having the base surface soldered to the substrate cannot be separated. In order to separate the package, the solder must be dissolved by heating, leading to such a problem that the overall device is badly influenced or re-mounting is inhibited due to deformation of the solder balls.
The insertion-mount type package allows multiplication of input/output pin electrodes as well as attachment/detachment of the package due to its structure. However, the socket electrodes receiving the pin electrodes manufactured by machining are so hard to miniaturize that the pin pitch is limited to about 500 μm to 1 mm. Further, the package manufactured by machining exhibits large dimensional dispersion, and requires a thickness of at least about 1 mm for attaining reliable electrical contact.
As to connection of an FPC, on the other hand, a connector prepared by covering an electrode formed by punching with a housing of resin is used for connecting FPCs or an FPC and a substrate such as a printed board with each other. In the FPC connector, however, refinement of the electrode size is limited due to machining, and it is difficult to miniaturize the connector and narrow the pitch of terminals due to securement of mechanical strength of the housing.